This invention relates to mechanisms for supporting ophthalmic instruments and more particularly to such mechanisms permitting adjustment of the instrument in two or three directions.
Ophthalmic instruments, such as slit lamps, non contact tonometers, objective refractors and subjective refractors require precise alignment of the instrument optical axis with the optical axis of the eye. The optics, mountings therefor and mechanisms associated therewith may weigh as much as 50 lbs. Such devices, because of the precision of alignment required, have usually been constructed with a base providing bidirectional horizontal motion that may be controlled with a single lever or a joy-stick. Such mechanisms provide finger-tip control in the horizontal motion. However, vertical control is usually obtained by rotating a screw to adjust the height of the instrument. A separate control is required for elevation and the construction of such units greatly increases the total weight of the unit.
It is an object of the present invention to provide improved finger-tip adjustment of elevation and at least one horizontal direction.
It is a further object of the present invention to provide a single lever control for three-directional motion.
It is a still further object of the present invention to provide a light-weight supporting mechanism for ophthalmic instruments which permits accurate alignment with little effort on the part of the practitioner.